This invention relates to an input device, in particular for a medical monitoring system, comprising a keyboard, display means and a processor connected with and/or controlling said keyboard and said display means.
A major problem for the designers of electronic instruments is the so-called man-machine-interface. Modern electronic instrumentation is not only used by technically experienced personnel like engineers, technicians etc., but also by personnel which is not very experienced in technical subject matter and sometimes even unwilling to operate complex instruments. An important and very critical example for such an application are all kinds of medical monitors. The man-machine-interface of such a monitor is the most sensitive component as the life of the health of a patient may depend on correct monitor controlling, whereas the operating personnel (nurses) usually is only experienced in medicine, but not in technique. Furthermore, the medical personnel is often in a stress situation when the monitor requires interaction. Therefore, ease of use and protection against malfunction caused by improper operation (e.g. suspend all patient alarms by accident) are decisive criteria for the design of the man-machine-interface and for the success of a monitor.
A lot of concepts for such man-machine-interfaces (also called human interfaces) are known in the art. A very simple concept is, of course, to assign a button, control knob or the like to any function or operating mode of the monitor. A lot of prior art monitors used this concept. Unfortunately, it does not work with complex, multifunctional monitors as the immense number of control buttons necessary for such a monitor would confuse the operating personnel and sometimes even lead to misadjustment. Attempts to overcome this disadvantage like cover doors covering those keys which are not required for normal operation are also limited to small or medium size monitors.
In addition, the concept "one button--one function" is absolutely unapplicable for configurable monitors (e.g. monitors with no fixed physiological parameter/channel relation).
Of course, the number of necessary buttons/knobs could be reduced by the use of one or more shift keys (as used in keyboards, pocket calculators etc.), but that would neither simplify the operating concept nor increase the transparency of the system.
Use of a normal, typewriter-like alphanumeric keyboard is only a solution for special cases as this requires a lot of familiarity with keyboard operation, experience with the system and readiness to spend time for man-machine interaction. Furthermore, the cramped environment in most medical applications does not allow to install such keyboards.
Another prior art concept which came up a couple of years ago is the use of softkeys, i.e. keys without a fixed label and with dynamically assigned function. The currently valid meaning of such a softkey is indicated by display means, e.g. softkey labels on a screen. By use of such softkeys, the necessary number of keys can be reduced drastically.
Prior art softkey concepts operate in the following way: In basic operation mode, some of the softkeys (at most all but one) are assigned to a specific function of the monitor. One of the softkeys is a "NEXT" or "CONTINUE" key which allows the user to step through a number of operating levels. Whenever the "NEXT" or "CONTINUE" softkey is pressed, the other softkeys are assigned different meanings which is indicated by appropriate softkey labels. Therefore, this concept enables the user to step through various operational levels. It is also possible to implement softkey operation in the form of a tree structure which guides the user by way of "yes/no" decisions to the final function.
Unfortunately, both softkey implementations are somewhat disadvantageous. The top-down structure is merely a modification of the "shiftkey" concept as the "NEXT" key could also be replaced by an appropriate number of shiftkeys. In this concept, the user can only recognize the current meaning of a key but not the "hidden" functions when he is in a certain operating level. Unexperienced users or users without technical background are often confused by such a concept.
The tree-structure concept--on the other hand--requires a lot of decisions and, therefore, a lot of thought. Users (such as nurses) who do not have enough time to concentrate on monitor operation may therefore be frustrated.
Both concepts are insofar inconsistent as they simply offer a multiplicity of choices, but do not implement a uniform, easy-to-learn model.